Self cleaning water filter

ABSTRACT

A self-cleaning water filter, coupled to a water flow having particulates therein, that includes a pair of canisters, each having a cylindrical wedge wire water filter screen. An elongated brush running the length of the screen is disposed between two confining walls also running the length of the screen to form a chamber. A elongated partition, including two sets of apertures, is used, along with the elongated brush, to divide the chamber into two particulate dislodge chambers and a drain subchamber. A drain is in fluid communication with the drain subchamber. During cleaning, the drain is opened and the screen is rotated against the brush for liberating the particulate contaminants and a limited amount of the water flow into the two dislodge subchambers. The particulate contaminants and the limited amount of water then pass through the apertures at a high velocity and into the drain subchamber which exits through the drain. Alternatively, a reverse flow of clean water can be used in combination with the elongated brush, for dislodging the particulate contaminants from the water filter. Finally, another variation of using a reverse flow of water for cleaning purposes is discussed whereby a stationary water filter is disposed in a system that isolates the water filter from the normal water flow during cleaning.

RELATED APPLICATIONS

[0001] This application is a divisional application of Ser. No.09/873,526 filed on Jun. 4, 2001, entitled SELF-CLEANING WATER FILTER,which in turn is a Continuation-in-Part of application Ser. No.09/737,411 filed on Dec. 15, 2000, which is a Continuation-in-Part ofapplication Ser. No. 09/417,404, filed on Oct. 13, 1999, now U.S. Pat.No. 6,177,022, which is a Continuation-in-Part of Co-Pending applicationSer. No. 09/014,447 filed Jan. 28, 1998, now abandoned, the latter threeof which are entitled SELF-CLEANING FUEL OIL STRAINER, and all of whoseentire disclosures are incorporated by reference herein.

BACKGROUND OF THE INVENTION

[0002] This invention relates generally to filter devices and, moreparticularly, to water system filters for small particulatecontaminants.

[0003] It is well-known that the mechanical cleaning of a filter surfacecan be accomplished by having a brush or scraper drag along the filtersurface where deposits have accumulated. In certain configurations, thebrush or scraper is mounted at one end between two walls but with asignificant portion of the brush or scraper projecting beyond the walls.Such configurations are shown in U.S. Pat. Nos. 148,557 (Gillespie etal.); 556,725 (Farwell); 740,574 (Kohlmeyer) and 793,720 (Godbe). Inconventional filter systems, the particulate contaminants are driven offthe filter surface and are deposited in a hopper or tank along with thefluid being filtered, thus discarding large amounts of the fluid beingfiltered.

[0004] The use of a brush, or high speed cleaning spray, disposedbetween a pair of walls for cleaning a cylindrical filter is known inthe art, as is disclosed in U.S. Pat. Nos. 5,423,977 (Aoki et al.) and5,595,655 (Steiner et al.) and Swiss Patent No. 22,863 (Zingg). Anothervariation employs a backwash that drives the particulate contaminantsoff of the cylindrical filter, as is disclosed in U.S. Pat. No.3,338,416 (Barry).

[0005] An exemplary use of such filters is in a water desalinationsystem that is available on ships. Shipboard water/salt water strainingis a specialized straining process. In particular, the water/salt waterflow is initially pre-strained for gross particulate contaminants, suchthat any particulate contaminants remaining in the water/salt water floware extremely small (e.g., <100 microns, with a large percentage beingless than 25 microns). As a result, where these small particulatecontaminants are captured by a downstream strainer (e.g., a wedge wirescreen strainer), both on and within the strainer surface, and thenlater dislodged during the strainer cleaning process, these extremelysmall particulate contaminants do not fall by gravity toward a drain butremain suspended in the water/salt water and will re-attach to thestrainer surface. Therefore, there remains a need for a cleaning devicethat can dislodge such extremely small particulate contaminants off ofthe downstream strainer surface, as well as from within the strainersurface, and then ensure that these particulate contaminants flow outthrough the drain rather than re-attaching to the strainer surface.

[0006] Thus, there is a need for an improved system for removingundesired particulate contaminants from a water/salt water flow andwithout interrupting that water/salt water flow to the engines, whileminimizing the amount of fluid removed therewith. It is to just such asystem that the present invention is directed.

SUMMARY OF THE INVENTION

[0007] A water cleaning system is disposed within a water flow havingparticulate contaminants therein. As mentioned earlier, the particulatecontaminants that need to be removed from the water flow are extremelysmall, less than 100 microns, and a large percentage of these less than25 microns, therefore do not settle out by gravity. The invention of thepresent application is well-suited to removing these small particulatecontaminants from the water flow and into a drain.

[0008] In particular, a water filter is disposed within a water flowhaving particulate contaminants therein. The water filter comprises: aporous member in fluid communication with the water flow such that thewater flow enters the porous member through a first porous membersurface and exits through a second porous member surface and wherein thewater flow deposits the particulate contaminants on the first porousmember surface; particulate-removing means disposed to be in closeproximity with the porous member for removing particulate contaminantsfrom the first porous member surface along substantially the entirety ofthe length of the first porous member surface; a pair of flow confiningwalls are disposed to be in close proximity with the first porous membersurface along substantially the entirety of the length of the firstporous member surface for defining a chamber; a partition divides thechamber into a first subchamber and a second subchamber along the lengthof the chamber; a drive mechanism is provided for displacing the porousmember for continuously directing particulate contaminants deposited onthe first porous surface past the particulate removing means forcontinuously dislodging the particulate contaminants from the firstporous member surface into the first subchamber; the partition includesfirst and second portions on opposite sides of the particulate removingmeans and each portion has a plurality of apertures for passing thedislodged particulate contaminants from the first subchamber into thesecond subchamber; and drain is in communication with the secondsubchamber and through which the dislodged particulate contaminants areremoved when the drain is opened.

[0009] A method is provided for cleaning a water flow having particulatecontaminants therein. The method comprises the steps of: disposing aporous member in fluid communication with the water flow such that thewater flow enters the porous member through a first porous membersurface and exits through a second porous member surface so that thewater flow deposits the particulate contaminants on the first porousmember surface; positioning a pair of flow confining walls adjacent thefirst porous member surface to define a chamber and positioning arespective flexible member between a respective flow confining wall andthe first porous surface member, and wherein the respective flexiblemembers are in contact with the first porous surface; positioning aparticulate-removing means closely-adjacent the porous member; dividingthe chamber into first and second subchambers with a partition havingfirst and second portions on opposite sides of the particulate removingmeans and each portion having a plurality of apertures to provide fluidcommunication between the first and second subchambers and wherein thesecond subchamber is in fluid communication with a drain when the drainis opened; displacing the porous member to permit theparticulate-removing means to dislodge particulate contaminants trappedon the first porous member surface into the first subchamber; andopening the drain to cause the dislodged particulate contaminants topass through the plurality of apertures into the second subchamber andout into the drain.

[0010] A water cleaning system is provided for use with a water flowhaving particulate contaminants therein. The cleaning system comprises:an inlet valve for controlling the water flow having particulatecontaminants therein forming a contaminated water flow and wherein thecontaminated water flow flows through a first output port of the inletvalve; a stationary porous member positioned in the contaminated waterflow that passes through the first output port and wherein thecontaminated water flow enters the stationary porous member through afirst porous member surface and exits through a second porous membersurface towards a second output port, and wherein the contaminated waterflow deposits the particulate contaminants on the first porous membersurface to form a clean water flow that flows toward the second outputport; an outlet valve coupled to the second output port for controllingthe clean water flow; a flow control means, operated during a porousmember cleaning process, having a flow control means input coupled to asource of water and a flow control means output coupled to the secondoutput port and wherein the flow control means controls a reverse flowof the clean water that flows from the second porous member surfacethrough the first porous member surface for dislodging the particulatecontaminants from the first porous member surface to form a contaminatedreverse flow of water; a drain valve coupled to the first output portfor directing the contaminated reverse flow of water towards a drainduring the cleaning process; and the inlet valve and outlet valve areclosed during the cleaning process.

[0011] A method is provided for cleaning a contaminated water flowhaving particulate contaminants therein. The method comprises the stepsof: positioning a stationary porous member in the contaminated waterflow such that the contaminated water flow enters the stationary porousmember through a first porous member surface and exits through a secondporous member surface toward an output port, and wherein thecontaminated water flow deposits the particulate contaminants on thefirst porous member surface; isolating the stationary porous member fromthe contaminated water flow during a cleaning process; passing a reverseflow of clean water from the output port and through the stationaryporous member from the second porous surface member surface to the firstporous member surface for dislodging the particulate contaminants fromthe first porous member surface to form a contaminated reverse flow ofwater; opening a drain to receive the contaminated reverse flow ofwater; discontinuing the reverse flow of clean water while closing thedrain to complete the cleaning process; and recoupling the stationaryporous member to the contaminated water flow.

[0012] A water filter system for use with a water flow havingparticulate contaminants therein. The water filter system comprises: aninlet valve for controlling the water flow having particulatecontaminants therein forming a contaminated water flow and wherein thecontaminated water flows through a first output port of the inlet valve;a stationary porous member positioned in the contaminated water flowthat passes through the first output port, and wherein the contaminatedwater flow enters the stationary porous member through a first porousmember surface and exiting through a second porous member surfacetowards a second output port, and wherein the water flow deposits theparticulate contaminants on the first porous member surface to form aclean water flow that flows towards the second output port; a thirdoutput port coupled to a drain through a drain valve; the inlet valvebeing closed while the drain valve is opened during a cleaning processfor generating a reverse flow of the water that flows from the secondoutput port towards the third output port, wherein the reverse flow ofthe clean water flows through the stationary porous member from thesecond porous member surface through the first porous member surface fordislodging the particulate contaminants from the first porous membersurface to form a contaminated reverse flow of water that flows into thedrain; and the drain valve being closed and the inlet valve being openedafter the cleaning process is completed.

DESCRIPTION OF THE DRAWINGS

[0013] Many of the intended advantages of this invention will be readilyappreciated when the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings wherein:

[0014]FIG. 1 is a block diagram of the water-desalination system inwhich the present invention is located;

[0015]FIG. 2 is a top view of the present invention;

[0016]FIG. 3 is a partial side view of the present invention;

[0017]FIG. 4 is a bottom view of the present invention;

[0018]FIG. 5 is a cross-sectional view of the present invention takenalong line 5-5 of FIG. 2;

[0019]FIG. 6 is partial sectional view taken along line 6-6 of FIG. 5;

[0020]FIG. 7 is a partial sectional view taken along line 7-7 of FIG. 5;

[0021]FIG. 8 is a cross-sectional view of the present invention using areverse flow of clean water/salt water as part of theparticulate-removing means;

[0022]FIG. 9 is a partial sectional view taken along line 9-9 of FIG. 8;

[0023]FIG. 10 is similar to FIG. 9 except that a different reverse flowdirection is depicted;

[0024]FIG. 11 is an enlarged, cross-sectional view of a portion of FIG.5, depicting different portions of the partition and one of theassociated wipers;

[0025]FIG. 12 is an enlarged, cross-sectional view of a portion of FIG.5, depicting the passageways in the particulate-removing means supportfor use with the alternative drain configuration;

[0026]FIG. 13 is a partial isometric view of the internal particulatechamber depicting the partition and one of the wipers comprising theshoes;

[0027]FIG. 14 is a schematic of a water/salt water cleaning system usinga stationary water/salt water strainer;

[0028]FIG. 15 is a variation of the water/salt water cleaning system ofFIG. 14 wherein the downline water/salt water flow is used as the sourceof the reverse clean water/salt water flow;

[0029]FIG. 16 is another variation of the invention of FIG. 15;

[0030]FIG. 17 is a cross-sectional view of a stationary filter, that canbe used in the systems shown in FIGS. 14-16, and having an ultrasonicgenerator disposed therein;

[0031]FIG. 18 is an enlarged view of the circled portion shown in FIG.17; and

[0032]FIG. 19 is a sectional view of the stationary filter taken alongline 19-19 of FIG. 17.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The following is a detailed description of the present invention.The present invention has wide application where straining very smallparticulate contaminants, less than 100 microns and large percentage ofthese are less than 25 microns, from a water/salt water flow isrequired, and is not limited to the environment shown in FIG. 1, as willbe discussed in detail below. The present invention is characterized asa non-disposable cleaning device, i.e., having a porous member that canbe cleaned rather than being thrown away. The term non-disposable isdefined as an item that does not require periodic replacement, e.g.,once a day, week or month. Thus, such a non-disposable item has obviousadvantages in environments where storage is limited and cleaning devicereplenishment facilities are unavailable, e.g., ocean-going vessels.Other example systems include power plants, cogeneration facilities,etc.

[0034] As an exemplary environment, Applicants have depicted a waterdesalination system 1 for disclosing the preferred embodiment; such awater desalination system 1 may be used on watercraft, e.g., ships andboats. However, it should be understood that it is within the broadestscope of the present invention that it can be used in any water cleaningsystem and it is not limited to a water desalination system.

[0035] Referring now in greater detail to the various figures of thedrawing, wherein like reference characters refer to like parts, there isshown in FIG. 1 at 520 a self-cleaning water filter of the presentinvention which forms a part of the system 1. The water filter system 1comprises five stages of straining/filtration followed by a reverseosmosis stage 6. A pump 2 pumps sea water into a ⅛″ perforation selfcleaning strainer 3 which discharges to a cyclone separator 4 (alsoreferred to in the art as a “centrifugal separator”), which dischargesto a 50 micron self cleaning wedge wire filter 5. The wedge wire filter5 discharges to the self-cleaning wire cloth (e.g., 10-20 micron) waterfilter 520 which, in turn, discharges to a 3 micron cartridge filter 6and finally through the reverse osmosis membrane 7 to a fresh wateruser/storage stage 8.

[0036] As shown more clearly in FIG. 2, the water filter 520 comprisestwo canisters 26 and 28 that are fed the main water flow withparticulates, e.g., the sea water, from the wedge wire filter 5 via acommon input manifold 30 (e.g., 2½ inch class 150 ANSI flanged input) atthe top portion of the filter 520. Each canister 26 and 28 has twoinputs from the common manifold 30, as indicated by inputs 32A and 32Bfor canister 26 and by inputs 34A and 34B for canister 28. Each canister26 and 28 comprises a cylindrical-shaped porous member 36 and 38,respectively, through which the sea water flows, as will be discussed indetail later. The porous members 36 and 38 comprise a screen selectedfrom the group consisting of wedge wire, wire cloth and perforatedmetal. In the preferred embodiment, the porous members 36 and 38comprise wedge wire screens, such as those manufactured by LeemFiltration Products, Inc. of Mahwah, N.J. It is also within the broadestscope of the present invention that the porous members 36 and 38 maycomprise wire cloth or perforated metal, as opposed to wedge wirescreens. One of the main features of the water filter 520 is its abilityto filter out fine particulate matter, e.g., particulates less than 100microns, where a large percentage of these are less than 25 microns.

[0037] Drive mechanisms 40 and 42 (FIG. 3) are provided to rotate therespective porous members 36 and 38 during the cleaning process abouttheir respective center axes, only one (44) of which is clearly shown inFIG. 5. Otherwise, during normal operation, the porous members 36 and 38remain stationary.

[0038] As can be seen in FIG. 2, sea water enters each canister throughits respective inputs and then flows around the periphery of each porousmember 36 and 38; in particular, sea water flow from inputs 32A and 32Bare shown by arrows 46A and 46B, respectively, and sea water flow frominputs 34A and 34B are shown by arrows 48A and 48B, respectively. Theinputs 32A and 32B are located on both sides of an internal particulatechamber 50 (FIG. 7, which comprises two dislodge subchambers 50A/50B anda drain subchamber 50C, all of which are discussed later) in canister26; similarly, although not shown, the inputs 34A and 34B in canister 28are also located on both sides of a internal particulate chamber, alsocomprising two dislodge subchambers and a drain subchamber. Thus,water/salt water input flow moves away from the chamber 50 and aroundthe periphery of the porous members 36 and 38 and then through them, asis discussed next.

[0039] Sea water flow through the porous member is more easily depictedin FIG. 5, which is a cross-sectional view of the canister 26, althoughit should be understood that the following discussion is applicable tothe other canister 28. The main sea water flow is through the porousmember 36, from an outside surface 37 to an inside surface 39, asindicated by the arrows 52, and down through the hollow interior 41 ofthe porous member 36. As the sea water then flows through the porousmember 36, particulate contaminants are then trapped against the outersurface 37 of the porous member 36. The filtered sea water exits into amain output 54 of the canister, as shown by the arrow 56. FIG. 4 is abottom view of both canisters 26 and 28 and it shows the main output 54of canister 26 and a main output 58 of canister 28 feeding into a commonoutput manifold 60. Thus, sea water flow through the filter 520 isbasically continuous.

[0040] When cleaning of the porous member 36 and 38 is required, asindicated by pressure drop across the filter 520 (as measured by apressure transducer, not shown), the drive mechanisms 40 and 42 areactivated to rotate the respective porous members. In addition, solenoidvalves 72 and 74 (FIG. 3) are activated to open respective drains (onlyone 76 of which is shown in FIG. 5), located directly below the drainsubchamber 50C, for diverting the particulate debris and a limitedamount sea water down through a respective drain, rather than throughthe main outlets 54 and 58. Furthermore, it is within the broadest scopeof this invention to include other alternative locations for the drain,e.g., along the chamber, rather than under it, as will be discussed indetail later. Opening of the drain 76 (or the alternative drain) is keptto a minimum to discard as little sea water as possible while flushingthe particulate contaminants from the chamber. Thus, for example, thedrain 76 can be open all or any part of the time that the porous members36 and 38 are rotating.

[0041] Cleaning of the porous members 36 and 38 is accomplished by theparticulate-removing means, only one of which is shown most clearly inFIGS. 5, 7, 8 and 9; as such, the following discussion applies to theparticulate-removal means in the canister 28 also. In the preferredembodiment, the particulate-removing means comprises an elongated wirebrush 62 that spans the length of the porous member 36. The brush fibersare in contact with the outside surface 37 of the porous screen 36 andthus bear on the outside surface 37 of the porous member 36 along itsentire length. The brush 62 forms the separation between the twodislodge subchambers 50A and 50B, while the majority of a brush support63 is disposed inside the drain subchamber 50C, as shown in FIG. 7.

[0042] As mentioned previously, the chamber 50 comprises the twodislodge subchambers 50A/50B and a drain subchamber 50C. The chamber 50comprises a pair of confining walls 64A and 64B, also running the lengthof the porous member 36, that enclose the brush 62/brush support 63. Thepurpose of these walls 64A and 64B is to contain the dislodgedparticulate debris within the chamber 50 so that substantially only seawater within this chamber 50 will be discharged through the drain 76 (oralternative drain 300, to be discussed later) during cleaning. Apartition 200, also running the length of the porous member 36, formsthe separation between the two dislodge subchambers 50A/50B and thedrain subchamber 50C. The partition 200 itself comprises a pair of outerflanges 202A/202B, a base wall 204 and sidewalls 206A/206B. The basewall 204 is secured between a particulate-removing means (e.g., brush 62or scraper) head 61 and the particulate-removing means support 63. Atthe bend between the sidewalls 206A/206B and the outer flanges202A/202B, the partition 200 comprises a plurality of apertures 212(FIGS. 7, 9, 11 and 12) that permit the passage of dislodged particulatecontaminants from the two dislodge subchambers 50A/50B to the drainsubchamber 50C. Because of the size of the apertures 212 (e.g., 0.094″diameter), once any particulate contaminants from the two dislodgesubchambers 50A/50B make their way through the partition 200, there isvery little chance that such particulate contaminants can find their wayback through the apertures 212 and ultimately return to the outersurface 37.

[0043] A drain passageway 75, through a strainer support housing 77, isalso shown in FIGS. 5. FIGS. 7 and 9 also show the passageway 75 inphantom.

[0044] At the extreme ends of the confining walls 64A and 64B,respective wipers 65A and 65B are secured to the outside surfaces of thewalls 64A and 64B, respectively, and which also run the length of theporous member 36. The wipers 65A and 65B (e.g., 316 stainless steel,half-hard) are coupled to the ends of the walls 64A and 64B usingfasteners 78 and plates 79. As can be seen most clearly in FIG. 13,wiper 65A comprises a plurality of spaced-apart shoes or runners 67 thatare in contact with the outer surface 37 of the porous member 36. Theseshoes 67 (e.g., 0.010″-0.015″ thickness and ¼″ wide and which may bespot-welded to the wiper 65A) serve to maintain the wiper 65A asufficient distance away from the outer surface 37 such that duringcleaning, while the porous member 36 is rotating (direction of rotationis shown by the arrow 161 in FIG. 7), the particulate contaminantsadhering to the outer surface 37 pass beneath the wiper 65A between theshoes and then are driven off of the outer surface 37 by theparticulate-removing means 62 and into the dislodge subchamber 50A. Thedrain subchamber 50C is in direct fluid communication with the drain 76(or alternative drain 300). When the drain 76 (or alternative drain 300)is open, any particulate contaminants suspended in the dislodgesubchamber 50A are pulled toward the apertures 212 in the partition 200and pass through them and out to the drain 76 (or 300).

[0045] Any remaining particulate contaminants which cannot bemechanically driven off of the surface 37 by the brush 62, e.g.,particulate contaminants lodged in between the outer surface 37 and theinside surface 39 of the porous member 36 (e.g., lodged in the wedgewire cells of a porous member 36 comprising wedge wire), are subjectedto a reverse pressure and are driven out of the surface 37 into thesecond dislodge subchamber 50B. In particular, unlike the first dislodgesubchamber 50A which is not totally closed off since the wiper 65Astands off from the outside surface 37 of the porous member 36, thesecond dislodge subchamber 50B forms a completely-closed off chamberbecause the wiper 65B does not include shoes and, therefore, is incontact with the outer surface 37 along its entire length. Thus, thesecond dislodge subchamber 50B is subjected completely to the influenceof the pressure differential created between the inside surface 39 ofthe porous member 36 and the opened drain pressure which is present inthe drain subchamber 50C, via the apertures 212. When the drain 76 (or300) is open, these particulate contaminants, lodged in between theouter surface 37 and the inside surface 39 of the porous member 36, aredriven out of that region by the reverse pressure differential and thenare suspended in the second dislodge subchamber 50B; this pressuredifferential also pulls these particulate contaminants toward theapertures 212 in the partition 200 and into the drain subchamber 50C forpassage through the drain 76 (or 300).

[0046] As pointed out earlier, the particulate contaminants are of anextremely small size, less than 100 microns, and a large percentage ofthese are less than 25 microns; as a result, these particulatecontaminants do not settle out by gravity into the drain but rather, dueto their small size, remain suspended in the sea water. The invention ofthe present application is well suited to overcome this problem asdescribed below.

[0047] It should be understood that the apertures 212 provide for fluidcommunication between the first dislodge subchamber 50A and the drainsubchamber 50C and for fluid communication between the second dislodgesubchamber 50B and the drain subchamber 50C. However, because theapertures 212 are small, they maintain a high velocity of particulatecontaminants from both the first and second dislodge subchambers 50A and50B into the drain subchamber 50C under the influence of the reversepressure differential. Such a high velocity cannot be sustained byreplacing the apertures 212 with a slot. Furthermore, replacing theapertures 212 with a slot would defeat the purpose of maintaining thetransferred particulate contaminants (i.e., particulate contaminantsthat have passed from the dislodge subchambers 50A/50B) in the drainchamber 50B since the particulate contaminants would not be precludedfrom making their way back to the outer surface 37 of the porous member36.

[0048] In particular, the advantage of using the plurality of apertures,as opposed to a slot of the type shown in U.S. Pat. No. 5,595,655(Steiner et al.), is that the plurality of apertures provides for arapid flow velocity as opposed to a low flow velocity for the slot. Forexample, if there are 21 apertures that form one set of apertures in thepartition 200, each having a diameter of approximately 0.094″, then thetotal area is approximately π(0.094″/2)²×21=0.1457 in². If, on the otherhand, a slot having a width of 0.094″ and a length of 12.594″ (i.e., thelength from the top of the uppermost aperture in the partition 200 tothe bottom-most aperture in the partition 200; this is a reasonableassumption since the Steiner et al. patent states that the slot issubstantially equal to the scraper length-Steiner et al. patent, col. 1,lines 61-62) is used, the area is 1.184 in². Thus, using a plurality ofapertures presents only ⅛ the area of the slot. As a result, for a givenflow rate (gallons/minute), the slot may provide flow velocity of 1ft/sec whereas the apertured partition generates a flow velocity of 8ft/sec. The higher velocity significantly reduces the chance that aparticulate will migrate backwards through the plurality of aperturesand re-attach to the porous surface 36.

[0049] It is also within the broadest scope of the present invention toinclude an alternative drain 300 configuration as shown most clearly inFIGS. 5, 8 and 12. To that end, a drain 300 is depicted along side thedrain subchamber 50C rather than disposed underneath the subchamber 50C,as discussed previously. The drain 300 comprises drain passageways 302,304 and 306 that form a portion of the particulate-removing meanssupport 63. The passageways 302-306 are coupled at one end to a commonmanifold 308 through which the dislodged particulate contaminants aredisposed of. As shown in FIG. 12, the other end of each passageway302-306 comprises a respective cross hole 310, 312, and 314 disposed inthe drain subchamber 50B. Thus, when a drain solenoid valve 316 (FIG. 5)is activated as discussed previously, particulate matter that has beendislodged from the outer surface 37 of the porous members 36/38 into thetwo dislodge subchambers 50A/50B, passes through the apertures 212 inthe partition 200 into the drain chamber 50B. From there, the dislodgedparticulate contaminants are driven into the cross holes 310-314,through the passageways 302-306 and then into the common manifold 308.Thus, particulate contaminants dislodged from the outer surface 37 ofthe porous members 36/38 would be driven into the alternative drain 300.

[0050] Alternatively, instead of using a single solenoid valve 316, itis within the broadest scope of this invention to include dedicatedsolenoid valves 318, 320 and 322 (FIG. 5) that individually couplerespective passageways 302-306 to the common manifold 308.

[0051] It is also within the broadest scope of the present inventionthat the term particulate-removing means include a brush, a scraper, orany equivalent device that is used to dislodge particulate contaminantsfrom the outside surface 37 of the porous members 36 and 38. Forexample, where larger particulate contaminants are to be filtered fromthe water flow, a scraper (not shown) can be used in place of the brush62.

[0052] It is also within the broadest scope of the present inventionthat the particulate-removing means also encompasses a reverse flow ofclean water for dislodging the particulate contaminants from the waterfilter 520; or a reverse flow of clean water in combination with theparticulate-removing member (e.g., brush or scraper), discussedpreviously.

[0053] In particular, as shown in FIGS. 8-10, a second embodiment of thepresent invention comprises a particulate-removing means that includesan elongated spraying element 151 comprising a plurality of ports 153.The elongated spraying element 151 is coupled to a pressure source 155(e.g., a pump, air supply, etc.) that recirculates clean water (whoseflow is indicated by the arrow 56) into the elongated spraying element151, during cleaning only, to create a high energy water spray thatemanates from each of the ports 153. As shown most clearly in FIG. 9,the direction of the high energy spray (indicated by the arrow 157) isfrom the inside surface 39 to the outside surface 37 of the porousmember 136. Thus, as the porous member 36 is rotated (directionindicated by the arrow 161) during cleaning, the high energy spraydrives the particulate contaminants from the outside surface 39 into thedislodge subchamber 50B.

[0054] It should be understood that the particulate-removing means maycomprise the elongated spraying element 151 alone for driving off theparticulate contaminants, or the particulate-removing means may comprisea particulate-removing member (e.g., a brush 62 or scraper) in additionto the elongated spraying element 151, as shown in FIGS. 8-9. Together,the elongated spraying element 151 and the particulate-removing member(e.g., brush 62 or scraper) act to dislodge the particulate contaminantsfrom the outside surface 37 of the porous member 36 during cleaning.When the particulate-removing member (e.g., a brush 62 or scraper) isused in combination with the elongated spraying element 151, thedirection of the high energy spray (indicated by the arrow 163) may beset to occur after the particulate-removing member dislodges some of theparticulate contaminants (FIG. 10), thereby driving particulatecontaminants into the second dislodge subchamber 50B.

[0055] The porous member 36, for use in this second embodiment,comprises an open lower end 137 (FIG. 8) to permit passage of theelongated spraying element 151 therethrough.

[0056] Another variation of the self-cleaning water filter that utilizesa reverse flow of clean water for cleaning purposes is depicted at 220in FIG. 14. In particular, as indicated by the arrow 165, during normaloperation, sea water enters through an inlet valve 167 to a water filter220. During normal operation, a drain valve 171 and a purge valve 173remain closed, as will be discussed in detail later. The water filter220 comprises a porous member 236, preferably having a wire clothconfiguration. The direction of the main sea water flow through theporous member 236 is given by the arrows 52 and is similar to the flowfor the porous members discussed previously, i.e., from an outsidesurface 37 of the porous member 236 to an inside surface (not shown) ofthe porous member 236 and then through the center portion 41 of theporous member 236. The cleaned sea water is then passed through anoutlet valve 175 in the direction of the arrow 177.

[0057] The cleaning process for the water filter 220 is different fromthe previous embodiments in that the porous member 236 does not moveduring cleaning. Instead, a reverse flow of clean water (the directionof this reverse flow is given by the arrow 179) is injected down throughthe center of the porous member 236, from the inside surface to theoutside surface 37 of the porous member 236. This reverse flow of cleanwater impacts the entire inside surface of the porous member 236 andflows to the outside surface 37 of the porous member 236, therebydislodging the particulate contaminants from the outside surface 37 ofthe porous member 236. Since this reverse flow acts through the entireporous member 236, there are no confining walls used. Thus, in thisembodiment, the particulate removal means comprises only the reverseflow of clean water. Because this reverse flow of clean water is appliedthrough the entire porous member 236, the water filter 220 must beisolated from the normal sea water flow during cleaning, as will bediscussed in detail below.

[0058] In particular, when cleaning is required, the inlet valve 167 andoutlet valve 175 are closed and the purge valve 173 and drain valve 171are opened. The purge valve 173 is coupled to a clean water reservoir181 which is under pressure (e.g., an air supply, whose input flow isindicated by the arrow 183 and having a valve 185 for maintaining airpressure in the reservoir 181. The downstream clean water, indicated bythe arrow 187, enters the reservoir 181 through a recharge valve 189).When the purge valve 173 and the drain valve are opened, the reverseflow of clean water 179 drives the particulate contaminants off of theoutside surface 37 of the porous member 236; this reverse flow, nowcontaining the dislodged particulate contaminants, flows out, asindicated by the arrow 191, through the drain valve 171. Once this flowof dislodged particulate contaminants passes to the drain, the purgevalve 173 and the drain valve 171 are closed and the input valve 167 andthe output valve 175 are opened, restoring normal sea water flow.

[0059] It should be understood that the continuous sea water flow isaccomplished by having a plurality (e.g., five to eight) parallel,non-rotating filter paths (not shown) that are coupled to the reservoir181 through respective purge valves 173. Thus, when any one non-rotationfilter path is being cleaned using the reverse water flow, the remainingparallel channels are operating under the normal sea water flow.

[0060] Another variation of this embodiment, depicted in FIG. 15, usesthe downstream clean water directly to create the reverse water flow. Inparticular, the purge valve 173 is coupled directly to the downstreamclean water flow. The sequence of valve openings/closings are similar tothat described previously. Thus, when the purge valve 173 and the drainvalve 171 are opened a pressure differential is created and the reverseflow of clean water, the direction indicated by the arrow 179, isgenerated directly from the downstream clean water flow.

[0061] Another variation of this embodiment is shown in FIG. 16 thatuses passive components such as a check valve 400 and a flow restrictingorifice 402 in place of the purge valve 173.

[0062] It should also be understood that the variations of FIGS. 15 and16, like that discussed with regard to FIG. 14, also comprise aplurality of parallel, non-rotating filter paths that permit thecontinuous flow of sea water when any one of the parallel, non-rotatingfilter paths is being cleaned by the reverse flow of clean water.

[0063] FIGS. 17-19 depict an exemplary station filter 220′, having anultrasonic generator 300 disposed therein, that can be used in thesystems shown in FIGS. 14-16 and, more preferably, to the systems ofFIGS. 15-16.

[0064] Before proceeding with a discussion of FIGS. 17-19, it should beunderstood that in FIGS. 14-16, the input flow 165 is shown in an upwarddirection from the bottom of the page toward the outlet flow 177 shownat the top of the page, for clarity only. The actual flow of any of thesystems shown in FIGS. 14-16 is exemplary only and may be in any numberof directions and, therefore, is not limited to those depicted in thosefigures. Thus, the orientation of the stationary filter 220′ shown inFIGS. 17-19 is simply inverted from that shown in FIGS. 14-16. Thus, the“top surface” 221′ in FIG. 17 corresponds to the “bottom” surface 221shown in FIGS. 14-16.

[0065] As will also be discussed in detail later, the input line intothe stationary filter 220′ is from the side of the canister 26′, at aninput port 32′, rather than from the “bottom” surface 221 shown in FIGS.14-16; the reason for this will also be discussed later. In addition, adedicated drain port 376 passes the dislodged particulate contaminantsaway from the stationary filter 220′ to a drain (not shown). Because ofthese port configurations, the input tee 291 in the systems of FIGS.14-16 is eliminated.

[0066] As shown in FIG. 17, the stationary filter 220′ is housed in thecanister 26′. On one side of the canister 26′ is the input port 32′while on the other side of the canister 26′ is the drain port 376; atthe bottom of the canister 26′ is an output port 54′. The ultrasonicgenerator 300 is disposed inside the hollow interior 41 of thestationary filter 220′. The inlet valve 167 is coupled to the port 32′and the drain valve 171′ is coupled to the drain port 376. The valves167/171′ and the ultrasonic generator 300 are operated by a controller(not shown) during the cleaning process of the stationary filter 220′itself, as will be discussed later.

[0067] As shown most clearly in FIG. 19, the stationary filter 220′ ispositioned inside a chamber formed by a circular wall 380. The wall 380comprises a plurality of sets (e.g., eight) of vertically-aligned holes(e.g., ¼″ diameter) dispersed around the circular wall 380 (see FIG.17); one hole 382 of each of the plurality of vertically-aligned holesis shown in FIG. 19. As will be discussed in detail later, the circularwall 380 acts to minimize the effects of the high velocityparticulate-contaminated input flow 165, as well as to deflect anddisperse the flow 165 all around the stationary filter 220′.

[0068] The stationary filter 220′ comprises three parts: (1) an outerwire cloth layer 384 (e.g., 5 microns); (2) an inner 40-50 mesh layer386; and (3) an inner perforated metal enclosure 388 (e.g., 16-18 gauge,stainless steel) all of which are microwelded together. The perforatedmetal enclosure 388 comprises staggered holes 390 (e.g., ¼″ diameter,see FIG. 17) that results in an overall surface area that isapproximately 50-60% open. The outer wire cloth layer 384 filters outthe particulate contaminants of incoming water/salt water flow thatpasses through the holes 382 in the circular wall 380; in particular, asthe incoming water/salt water flow 165 passes through an outer surface385′ (see FIG. 18) of the wire cloth layer 384 to an inner surface 385″of the wire cloth layer 384, the particulate contaminants lodge againstthe outer surface 385′. The 40-50 mesh layer 386 disperses the cleanedinput flow around the periphery of the perforated metal enclosure 388and through all of the holes 390 therein. The cleaned water/salt waterflow then flows downward through the hollow interior 41 of thestationary filter 220′ and through the output port 54′.

[0069] Although not shown, another version of the stationary filter 220′comprises only two parts: (1) an outer wire cloth layer (e.g., 5-20microns) directly over a wedge wire inner layer with {fraction (5/16)}inch slot openings between the turns of wedge wire. Advantages of thissecond version of the stationary filter 220′ are that it allows a 90%open area as well as more direct contact with the backwash flow and theultrasonic waves.

[0070] As can also be seen most clearly in FIG. 19, several continuoussupport members 392 are disposed between the outer wire cloth layer 384of the stationary filter 220′ and the circular wall 380. Thesecontinuous support members 392 form independent sectors 394 (e.g.,eight, FIG. 19) around the periphery of the wire cloth layer 384. Asmentioned earlier, during normal sea water flow, the effects of the highvelocity particulate-contaminated input flow 165 are minimized by thepresence of the circular wall 380 and the sectorization formed by thecontinuous support members 394; these sectors 394 segment the input flow165 so that the input flow 165 impacts the wire cloth layer 384 aroundthe entire stationary filter 220′. In particular, once theparticulate-contaminated input flow 165 in each sector 394 passesthrough the vertically-aligned apertures 382, the input flow 165encounters the outer surface 385′ of the wire cloth layer 384 whichtraps the particulate contaminants therein. As also mentioned earlier,the cleaned water then passes through the 40-50 mesh layer 386 whichdisperses the cleaned input flow around the periphery of the perforatedmetal enclosure 388 and through all of the holes 390 therein. Thecleaned water flow then flows downward through the hollow interior 41 ofthe stationary filter 220′ and through the output port 54′

[0071] The stationary filter 220′ is releasably secured inside thecanister 26′ using four tie bars 396 (FIG. 19) that couple between alower baseplate 398 and an upper securement surface 400. To properlyseal the stationary filter 220′ inside the canister 26′ an upper annularseal 402 (e.g., rubber, see FIG. 18) and a lower annular seal 404 (e.g.,rubber) are used.

[0072] The ultrasonic generator 300 (e.g., the Tube ResonatorRS-36-30-X, 35 kHz manufactured by Telsonic USA of Bridegport, N.J.) isreleasably mounted in the hollow interior 41 of the stationary filter220′. In particular, an elongated housing 393 of the ultrasonicgenerator 300 is suspended in the hollow interior 41 of the stationaryfilter 220′. Thus, when the reverse flow of clean water/salt water 179occupies the hollow interior 41, the ultrasonic generator 300 isenergized wherein the ultrasonic energy is applied to the wire clothlayer 384 in the direction shown by the arrows 395 through the holes390. The elongated housing 393 is attached to an electrical connector397 which forms the upper portion of the ultrasonic generator 300. Theelectrical connector 397 is then releasably secured to the canister 26′(e.g., a nut 399). A wire harness 401 provides the electrical connectionto the ultrasonic generator 300 from the controller (not shown). In thisconfiguration, it can be appreciated by one skilled in the art, that theultrasonic generator 300 and stationary filter 220′ can beinstalled/replaced rather easily without the need to disconnect anyplumbing from the input port 32′, output port 54′ or drain port 376.

[0073] During normal operation, the inlet valve 167 is open and thedrain valve 171′ is closed, thereby allowing the contaminated water/saltwater flow 165 to be cleaned by the stationary filter 220′ as discussedabove. When the stationary filter 220′ itself is to be cleaned, thecontroller (not shown) closes the inlet valve 167 while opening thedrain valve 171′. As a result, a high pressure reverse flow 179 of cleanwater flows from the output port 54′ and through the three-partstationary filter 220′ and out through the drain port 376. As thisreverse flow 179 passes through the wire cloth layer 384, theparticulate contaminants are dislodged from the outer surface 385″ ofthe wire cloth layer 384 and then driven out through the drain port 376.It should be noted that during this high pressure reverse flow 179, thecontinuous support members 392 also act to prevent the wire cloth layer384 from separating from under laying support. The reverse flow 179 isapplied for a short duration (e.g., approximately 4-5 seconds).

[0074] At the end of this application, and while there is still cleanwater in the hollow interior 41 but where the flow 179 is simplymigrating (e.g., movement of clean water in inches/minute) rather thanflowing, the controller (not shown) activates the ultrasonic generator300 for a longer duration (e.g., 30 seconds to a couple of minutes) toprovide for further cleaning of the wire cloth layer 384 by usingultrasonic energy to dislodge any remaining particulate contaminants inthe wire cloth layer 384 into the migrating water flow and out throughthe drain port 376.

[0075] Without further elaboration, the foregoing will so fullyillustrate our invention and others may, by applying current or futureknowledge, readily adapt the same for use under various conditions ofservice.

We claim:
 1. A water filter disposed within a water flow havingparticulate contaminants therein, said water filter comprising: a porousmember in fluid communication with the water flow such that the waterflow enters said porous member through a first porous member surface andexits through a second porous member surface, said water flow depositingthe particulate contaminants on said first porous member surface;particulate-removing means disposed to be in close proximity with saidporous member for removing particulate contaminants from said firstporous member surface along substantially the entirety of the length ofsaid first porous member surface; a pair of flow confining wallsdisposed to be in close proximity with said first porous member surfacealong substantially the entirety of the length of said first porousmember surface for defining a chamber; a partition dividing said chamberinto a first subchamber and a second subchamber along the length of saidchamber; a drive mechanism for displacing said porous member forcontinuously directing particulate contaminants deposited on said firstporous surface past the particulate removing means for continuouslydislodging the particulate contaminants from said first porous membersurface into said first subchamber; said partition including first andsecond portions on opposite sides of said particulate removing means andeach portion having a plurality of apertures for passing the dislodgedparticulate contaminants from said first subchamber into said secondsubchamber; and a drain being in communication with said secondsubchamber and through which the dislodged particulate contaminants areremoved when said drain is opened.
 2. The water filter of claim 1wherein said plurality of apertures are of sufficient area to generate arapid velocity of dislodged particulates from said first subchamber intosaid second subchamber and wherein when said drain is opened a drainflow is created and wherein said plurality of apertures are linearlyarranged to define an effective aperture length and wherein eachaperture comprises a diameter, said rapid velocity of dislodgedparticulate contaminants being approximately eight times a velocity ofdislodged particulate contaminants established by a slot having saideffective aperture length and a width comprising said diameter for agiven drain flow.
 3. The water filter of claim 1 wherein saidparticulate removing means comprises a brush or scraper closely adjacentsaid first porous member surface and wherein said first subchamber isdivided into a first dislodge subchamber and a second dislodgesubchamber by said brush or scraper and wherein: said first dislodgechamber is formed between said first porous member surface, one of saidconfining walls, said brush or scraper, said partition and a firstflexible member disposed between said one of said confining walls andsaid first porous member surface; and said second dislodge chamber isformed between said first porous member surface, the other of saidconfining walls, said brush or scraper, said partition and a secondflexible member that is disposed between said other of said confiningwalls and said first porous member surface.
 4. The water filter of claim3 where said first flexible member comprises a plurality of shoes thatare in contact with said first porous member surface for disposing saidfirst flexible member closely adjacent said first porous member surface.5. The water filter of claim 4 wherein said first flexible member isdisposed away from said first porous member surface in the range of0.010 inches to 0.015 inches.
 6. The water filter of claim 1 whereinsaid particulate-removing means comprises a spraying element positionedclosely adjacent said second porous member surface and opposite saidpair of confining walls for generating a reverse flow of clean water,said reverse flow being directed from said second porous member surfacethrough said first porous member surface for dislodging the particulatecontaminants away from said first porous member surface into said firstsubchamber.
 7. The water filter of claim 6 wherein said spraying elementcomprises an elongated lumen comprising a plurality of ports and coupledto a pressure source of clean water.
 8. The water filter of claim 1wherein said porous member comprises a cylindrical-shaped filter andwherein said first porous member surface is the outer surface of saidcylindrical-shaped filter and wherein said second porous member surfaceis the inner surface of said cylindrical-shaped filter.
 9. The waterfilter of claim 8 wherein said cylindrical-shaped filter screencomprises a screen selected from the group consisting of wedge wire,wire cloth and perforated metal.
 10. The water filter of claim 9 whereinsaid cylindrical-shaped filter screen comprises a wedge wireconfiguration for trapping particulate contaminants.
 11. The waterfilter of claim 10 wherein said cylindrical-shaped filter screencomprises a wedge wire configuration for trapping particulatecontaminants as small as approximately 25 microns.
 12. The water filterof claim 1 wherein said particulate removing means comprises a brush orscraper and wherein said drain comprises: a plurality ofparticulate-removing means supports that include respective internalpassageways that are in fluid communication with said second subchamber;a common manifold to which said respective internal passageways arecoupled; and a drain valve coupled to said common manifold forcontrolling the opening and closing of said drain.
 13. The water filterof claim 1 wherein said particulate removing means comprises a brush orscraper and wherein said drain comprises: a plurality of brush orscraper supports that include respective internal passageways that arein fluid communication with said second subchamber; a respectivepassageway valve coupled to each passageway for controlling the passageof particulate contaminants through said respective passageway; and acommon manifold coupled to said respective passageway valves forconveying particulate contaminants out of said passageways.
 14. Thewater filter of claim 1 wherein said porous member comprises acylindrical-shaped filter and wherein said first porous member surfaceis the outer surface of said cylindrical-shaped filter and wherein saidsecond porous member surface is the inner surface of saidcylindrical-shaped filter.
 15. The water filter of claim 14 wherein saiddrive mechanism displaces said filter by causing it to rotate.
 16. Thewater filter of claim 15 wherein said confining walls compriserespective outer surfaces away from said member and wherein said fluidcommunication comprises a first input water flow and a second inputwater flow on a respective outer surface away from said member.
 17. Thewater filter of claim 1 wherein said porous member traps particulatecontaminants as small as approximately 25 microns.
 18. The water filterof claim 17 wherein said porous member comprises a screen selected fromthe group consisting of wedge wire, wire cloth and perforated metal. 19.The water filter of claim 1 wherein the water flow is a flow of seawater.
 20. A method for cleaning a water flow having particulatecontaminants therein, said method comprising the steps of: disposing aporous member in fluid communication with the water flow such that thewater flow enters said porous member through a first porous membersurface and exits through a second porous member surface so that thewater flow deposits the particulate contaminants on said first porousmember surface; positioning a pair of flow confining walls adjacent saidfirst porous member surface to define a chamber and positioning arespective flexible member between a respective flow confining wall andsaid first porous surface member, said respective flexible members beingin contact with said first porous surface; positioning aparticulate-removing means closely-adjacent said porous member; dividingsaid chamber into first and second subchambers with a partition havingfirst and second portions on opposite sides of said particulate removingmeans and each portion having a plurality of apertures to provide fluidcommunication between said first and second subchambers, said secondsubchamber being in fluid communication with a drain when the drain isopened; displacing said porous member to permit saidparticulate-removing means to dislodge particulate contaminants trappedon said first porous member surface into said first subchamber; andopening the drain to cause the dislodged particulate contaminants topass through said plurality of apertures into said second subchamber andout into the drain.
 21. The method of claim 20 wherein one of saidrespective flexible members is positioned to be in contact with saidfirst porous member surface at discrete locations.
 22. The method ofclaim 21 wherein said step of displacing said porous member comprisesdisplacing said first porous member surface transversely in front ofsaid particulate-removing means in a first direction, said first porousmember surface passing said one of said respective flexible members thatis in contact with said first porous member surface at discretelocations before passing in front of said particulate-removing means.23. The method of claim 20 wherein said particulate removing meanscomprises a brush or scraper positioned closely adjacent said firstporous member surface.
 24. The method of claim 20 wherein saidparticulate removing means comprises a spraying element positionedclosely adjacent said second porous member surface opposite said pair ofconfining walls for generating a reverse flow of clean water, saidreverse flow being directed from said second porous member surfacethrough said first porous member surface for dislodging the particulatecontaminants away from said first porous surface into said firstsubchamber.
 25. The method of claim 20 wherein the water flow is a flowof sea water.